Observation of K+→π+π0π0γ decay Artamonov, A. V.; Bychkov, V. N.; Donskov, S. V. ...
The European physical journal. C, Particles and fields,
04/2024, Volume:
84, Issue:
4
Journal Article
Peer reviewed
Open access
The
K
+
→
π
+
π
0
π
0
γ
decay is observed by the OKA collaboration. About 60 events of the decay observed with signal:noise
≈
1
. The branching ratio obtained by normalization to
K
+
→
π
+
π
0
π
0
is ...measured to be
(
3.7
±
0.9
(
s
t
a
t
)
±
0.3
(
s
y
s
t
)
)
×
10
-
6
for
E
γ
∗
>
10
MeV
. The branching ratio,
γ
energy spectrum and angular distribution are consistent with ChPT prediction.
A high-statistics data sample of the
K
+
decays is recorded by the OKA collaboration. A missing mass analysis is performed to search for a light invisible pseudoscalar axion-like particle (ALP)
a
in ...the decay
K
+
→
π
+
π
0
a
. No signal is observed, and the upper limits for the branching ratio of the decay are calculated. The
90
%
confidence level upper limit changes from
2.5
·
10
-
6
to
2
·
10
-
7
for the ALP mass from 0 to 200 MeV/
c
2
, except for the region of
π
0
mass, where the upper limit is
4.4
·
10
-
6
.
•Ca-deficient HA and carbonate CHA apatites were obtained under US or MW radiation.•The influence of US or MW radiation significantly shortens HA formation.•The cooling of reaction system has led to ...the formation of pure HA.•US and MW influences increase the bioactivity of apatites.•Thermal stability of apatites, synthesized under US and MW radiations, decreases.
The samples of hydroxyapatite and carbonate substituted hydroxyapatite (CHA) were obtained under the influence of physical factors, namely ultrasound (US) and microwave (MW) radiations. The results of Fourier transform infrared spectroscopy and X-ray diffraction analysis have proved the formation of the calcium deficient hydroxyapatite and B-type CHA with the Ca/P ratio in the ranges 1.62–1.87. In vitro studies have showed the increased bioactivity of the samples, synthesized under the influence of physical factors as compared to the standard ones. The samples of both groups, synthesized under the influence of 600 W MW, have shown the greatest stability in biological environment. In vivo tests confirm that obtained under US and MW radiations hydroxyapatite-based biomaterials are biocompatible, non-toxic and exhibit osteoconductive properties. The usage of US and MW radiations can significantly shorten the time (up to 5–20 min) of obtaining of calcium deficient hydroxyapatite and B-type CHA in nanopowder form, close in structure and composition to the biological hydroxyapatite.
Study of K+→π0e+νγ decay with OKA setup Polyarush, A. Yu; Akimenko, S. A.; Artamonov, A. V. ...
The European physical journal. C, Particles and fields,
02/2021, Volume:
81, Issue:
2
Journal Article
Peer reviewed
Open access
Results of a study of the
K
+
→
π
0
e
+
ν
γ
decay at OKA setup are presented. More than 32,000 events of this decay are observed. The differential spectra over the photon energy and the ...photon–electron opening angle in kaon rest frame are presented. The branching ratios, normalized to that of
K
e
3
decay are calculated for different cuts on
E
γ
∗
and
c
o
s
Θ
e
γ
∗
. In particular, the branching ratio for
E
γ
∗
>
30
MeV and
Θ
e
γ
∗
>
20
∘
is measured R =
B
r
(
K
+
→
π
0
e
+
ν
e
γ
)
B
r
(
K
+
→
π
0
e
+
ν
e
)
= = (0.587±0.010(
stat
.)±0.015(
syst
.))
×
10
-
2
, which is in a good agreement with ChPT
O
(
p
4
)
calculations.
•The α-Gal A/lysoGb3 ratio is a promising marker of Fabry disease in females.•A correlation between lysoGb3 concentration and age was found.•LysoGb3 levels were different between ...asymptomatic/symptomatic FD female patients.
Fabry disease (FD MIM:301500) is an X-linked lysosomal storage disorder caused by mutations in the GLA gene. Deficient activity of its product, lysosomal enzyme α-galactosidase A (α-Gal A), leads to excessive accumulation of glycosphingolipids in cells of multiple organs.
The establishing of the diagnosis is challenge in female patients because of milder clinical manifestation and normal α-Gal A activity.
The globotriaosylsphingosine (lysoGb3) is described as a more sensitive diagnostic biomarker for females with pathogenic mutation in the GLA gene.
Thus, the aim of this study is to improve the biochemical diagnostic efficiency for FD in females.
Here we report the α-Gal A/lysoGb3 ratio as the novel biochemical criteria for diagnosis of female patients with FD, using dried blood spots (DBS) as test samples. It showed 100% sensitivity in distinguishing our group of 35 female patients from control (n = 140). Whereas measurement of α-Gal A and lysoGb3 alone showed 8.6% and 74.4% respectively.
A new approach of using the ratio of α-Gal A activity to lysoGb3 concentration in DBS may provide a more accurate screening tool for identification of FD females.
The paper describes a qualitatively new CNET library of few-group neutron cross sections designed to simulate neutronic parameters in RBMK-1000 reactors. The CNET library makes use of a neural ...network to approximate cell (node) constants registered with a large group of full-scale calculations of various reactor states. We explore problems faced when approximating neutron cross sections using machine learning techniques and, specifically, neural networks. An approach is described to solve these problems following JSC VNIIAES guidelines to develop a new CNET library. The results of validating the MNT-CUDA high-accuracy program featuring the CNET library are presented.
The
T
-odd correlation
, which is the mixed product of the momenta of
,
, and γ in the system of rest of the kaon divided by
, has been measured in the
K
+
→ π
0
e
+
ν
e
γ radiative decay among 101 ...200 candidate events detected at the OKA setup. The asymmetry of the distribution in
is characterized by the ratio
, where
is the number of events with positive (negative) ξ. The value
= (+0.1 ± 3.9(stat.) ± 1.7(syst.)) × 10
–3
or
(90% C.L.) has been obtained.
An approach is proposed to expand the range of operational neutronic problems to be solved through combining various models of neutron transport (multigroup with detailed geometry description and ...two-group with a homogeneous description) in separate parts of the design area. The approach is deployed in the high-precision engineering program MNT-CUDA (version 2.0), capable of full-scale reactor engineering calculations using the Monte Carlo group method with an option of detailed description of neutron transport over the entire system or inside specific areas. The algorithm proposed uses GPU parallel computing. New features of the program are demonstrated. The results of studying the accuracy of combined calculations are presented and analyzed.
For the first time, the oscillatory behavior during CO oxidation over Ni foil has been discovered under atmospheric pressure conditions in the temperature range of 570–630 °C. The oscillatory ...behavior occurred in CO excess in contrast to the well-known oscillations during CO oxidation over Pt, Pd, Ir, and Ru. The periodic variation of oxygen imbalance together with the variation of color changes during the oscillations indicated that the oscillations were closely connected with the reversible oxidation of Ni to NiO. The observation of oscillations in a pulse supply mode proved their kinetic origin. The oscillations were accompanied by the propagation of the oxidation and reduction fronts which could be observed with the naked eye.
Graphical Abstract
Temporal and spatial self-organization during CO oxidation over Ni foil.
On the statistics of ~1.7 × 10
8
interactions of positively charged kaons on copper nuclei, coherent events of the
K
+
π
0
system production are selected. The cross sections for the Coulomb and ...coherent strong components and their interference in the region of the
K
*(892) meson are measured. The partial width for the decay
K
*(892) →
K
+
γ is determined. When studying the mass spectrum of the
K
+
π
0
system, an effect which can be interpreted as the interference of the chiral anomaly and the
K
*(892)
s
-channel amplitudes is found. This gives an estimate for the ratio of the observed amplitude of the chiral anomaly to the theoretical one:
A
exp
/
A
th
= 0.9 ± 0.24(stat.) ± 0.3(syst.).
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